We all have other obligations in life, which require our time. Also the number of fail launches of all sorts of fail coins really got the best of us, none of us get any joy out of running a pool anymore.
Yup, I like to always do some solo mining on newly launched coins (have a separate rig for this), but in the last weeks it really has been dramatic with new coins.
The last being Rotocoin yesterday with a way to late launch, followed by an insane difficulty after just a few blocks.